Add abstract testnet to metamask and arbitrum sepolia dapp

What is a testnet? A testnet faucet provides web3 developers with free tokens for deploying, testing, and optimizing smart contracts on test blockchains such as Sepolia, Goerli, and Mumbai. Because smart contracts on public, mainnet blockchains like Ethereum and Polygon require gas fees to run smart contracts, testnets provide blockchain developers with a network that mirrors production blockchain environments without requiring gas fees that cost real money. Get Testnet Tokens! blockchain app download apk claim bsc testnet3 token ethereum free token type beat chainid for goerli sepolia testnet smart contract testing juno testnet keplr